Ratchet wrench provided with supplemental head turning means



Dec. 13, 195 G'. w. BLACKBURN RATCHET WRENCH PROVIDED WITH SUPPLEMENTALHEAD TURNING MEANS 2 Sheets-Sheet 1 Filed March 23, 1953 g NEIF Dec. 13,1955 ca. w. BLACKBURN 2,726,563

RATCHET WRENCH PROVIDED WITH SUPPLEMENTAL HEAD TURNING MEANS Filed March25, 1953 2 Sheets-Sheet 2 X F/GSA. F/6. 3B.

F/a. 5A.

mu /1m 650265 )11 awe/rave d {ll h United States Patentfi RATCHET WRENCHPROVIDED WITH SUPPLE- MENTAL HEAD TURNING MEANS George WilliamBlackburn, Fulllam, London, England Application March 23, 1953, SerialNo. 344,104

Claims priority, application Great Britain March 29, 1952 8 Claims. (Cl.s1-ss.1

This invention relates to hand tools for imparting turning movement to awork element such as a nut, screw or stud, of the kind comprising aratchet wheel to which a socket member is attached, the socket memberbeing adapted to engage the work element in order to transmit therotational movement of the ratchet thereto. The principal object of theinvention is to provide an improved hand tool of the kind describedwhich will allow speedy operation in restricted positions and, undernormal conditions, will allow nuts, studs, screws or the like to beturned at greatly increased speeds.

According to the invention, a hand tool of the kind described, comprisesa hollow head having an opening therein, a ratchet wheel mounted withinsaid head and accessible via said opening, at least onespring-controlled pawl carried within and by said head and adapted toeffect rotation of said ratchet wheel in one direction only by bodilyrotation of said head about the axis of said ratchet wheel, a stirruppiece rotatably mounted about the axis of said ratchet wheel, a pivotrod carried by said stirrup piece, a spring-controlled pawl carried bysaid pivot rod and adapted on bodily rotation about the axis of saidratchet wheel to effect rotation of said ratchet wheel in the samedirection as before, a bell-crank lever fulcrummed in said head, one armof said lever being formed with a guide slot with which said pivot rodis in sliding engagement, and means for rotating said bellcrank leverabout said fulcrum.

According to a preferred embodiment, the means for effecting rotation ofthe bell-crank lever consists of a rod which passes through a hollowhandle secured to the hollow head, said rod being pivotally connected atone end to the lever and at the other end to a trigger mechanism pivotedon the handle.

Further important features of the invention will appear hereinafter.

The ratchet wheel can therefore be turned by means of the main pawl byswinging the spanner handle through an angle or by means of the movingpawl by imparting a movement by any suitable means to an actuating rodoperating the bell-crank lever.

The ratchet head will contain a stud of square or other suitablepolygonal section to which any one of a number of socket members may befitted. It will be possible for the stud to protrude from the upper orlower face of the ratchet wheel in order that forces may be transmittedin clockwise and anti-clockwise directions.

One embodiment of a ratchet spanner according to the invention will nowbe described wtih reference to the accompanying drawings, in which:

Figure l is a plan View of the ratchet head with the handle in section,

Figure 2 is a side view corresponding to Figure -1 partly sectioned withthe side casing of the head removed, and

Figures 3 to 6 illustrate details.

Referring to Figures 1 and 2, the spanner comprises a hollow handle 1and a head 2 containing the ratchet mechanism. A ratchet wheel 3 isfitted in the head casing and contains a hexagonal hole 4 to hold asuitable driving stud to engage a socket member or work element.

A main pawl 5 is embedded in a projection of metal from the side of thehead casing and operated by a suitably placed spring 6. A pin 7 is thepivot for a moving pawl 8 and supports the moving pawl in the upper andlower halves of a stirrup piece 9. The moving pawl will be suitablyoperated by a spring normally bearing against the stirrup piece. Abell-crank lever 10 is pivoted about a pin 11 which is fixed in the headcasing. The bellcrank lever normally has a strengthening web 12 joiningthe top and bottom sections. The top and bottom sec tions of thebell-crank lever contain a guide slot 13 into which extensions of themoving pawl pin 7 above the surface of the top and bottom sections ofthe stirrup piece fit. An actuating rod 14 is joined to the bell-cranklever at the journal 15 and suitably fastenedto this journal. A trigger21 is pivoted at pin 17 situated on a suitable web 16 fastened to orpart of the spanner handle. The other end of the actuating rod 14 issuitably fastened to the trigger journal 18. A return spring 19 isprovided to return the trigger after operation.

The device operates in the following manner:

When the trigger 21 is depressed, the actuating rod 14 will be pulleddownwards and the bell-crank lever 10 will pivot about pin 11. Themoving pawl pin 7 will be forced to move in the guide slot 13, and thestirrup piece 9 carrying the moving pawl 8 will be rotated through anangle about the centre of the ratchet wheel. The ratchet wheel will beturned by the moving pawlv through a similar angle. When the trigger isreleased, the ratchet wheel will be retained by the main pawl 5, but thereturn spring under the trigger, operating through the actuating rod 14,will return the moving pawl, stirrup piece, and bell-crank lever totheir original positions. It will be possible therefore for the ratchetwheel to be turned by means of the main pawl 5 by swinging the handle inan are or by means of the moving pawl 8 by operating the trigger. 7

Various modifications of the mechanism are possible to increase theefficiency of its operation. For example, a recess 20 can be formed inthe handle stock to allow a greater angular movement to the trigger andtherefore a great angular movement of the bell-crank lever.

Means for adjusting the mechanism or for taking up wear can beincorporated at journal 15 at the upper end of the actuating rod. Theupper end of the actuating rod may be threaded, as shown in Figure 1,and screwed into a hole in journal 15 suitably threaded to receive it.

The movement of the bell-crank lever may be limited by arranging for thetrigger to contact the surface of the handle, when open at A, and whendepressed at B.

Certain modifications are possible in connectionrwith the structure ofthe stirrup piece. Figure 3 (B) shows a complete stirrup piececonsisting of two sections, a top and a bottom one, each incorporating aflange X. The flanges on the top and bottom sections are fastenedtogether as at Y by riveting, welding or by other suitable means, whenthe stirrup piece is in position about the ratchet wheel. The said web Ymay be utilised to bear the reaction of the moving pawl control spring.

The initial movement of the bell-crank lever may be assisted byelongating slightly the holes in the stirrup piece through which themoving pawl pivot pin passes, see Figure 4. The elongation will be in aline at right angles to the axis of the guide slot when the bell-cranklever is in the initial position as shown in Figure 1. This elongationwill allow the starting torque to be applied directly to the ratchetwheel and will allow an initial movement of the wheel to be made withlittle impedance or drag from the stirrup piece.

Various modifications can be made of the bellcrank lever. For exampleFigure 5 shows a bell-crank Patented Dec. 13, 1955 lever incorporating asuitable web X for additional strength. The slope of the guide slot maybe changed to give a slightly more efiicient torque to the ratchet wheelfor extreme positions of the bell-crank lever. Figures 6 A and B showtwo possible variations in slot slope. Figure 6 (A) shows a bell-cranklever with the slot axis along a line joining the centre of the pivot Xand the centre of the moving pawl pin in its initial position as showndotted at Y. Figure 6 (B) shows a bell-crank lever with the slot axis atan angle to a line joining the centre of the pivot X and the centre ofthe moving pawl pin in its initial position as shown dotted at Y. Thisslope will give a slightly improved torque to the ratchet wheel over thefinal angular movement of the bell-crank lever, since the force will beapplied more obliquely to the ratchet wheel. The type of guide slotshown in Figure 6 (B) is incorporated in the ratchet spanner illustratedin Figures 1 and 2.

The main pawl may be mounted on a pivot fitted in the head casing or maybe embedded in a suitable recess in the head casing.

I claim:

1. A hand tool for giving a turning movement to a work element such as anut, screw or stud, comprising a hollow head having an opening therein,a ratchet wheel mounted within said head and accessible via saidopening, at least one spring-controlled pawl carried within and by saidhead and adapted to effect rotation of said ratchet wheel in onedirection only by bodily rotation of said head about the axis of saidratchet wheel, a stirrup piece rotatably mounted about the axis of saidratchet wheel, a pivot rod carried by said stirrup piece, aspring-controlled pawl carried by said pivot rod and adapted on bodilyrotation about the axis of said ratchet wheel to effect rotation of saidratchet wheel in the same direction as before, a bell-crank leverfulcrumed in said head, one arm of said lever being formed with a guideslot with which said pivot rod is in sliding engagement, and means forrotating said bell-crank lever about said fulcrum.

2. A hand tool according to claim 1, wherein the guide slot in saidbell-crank lever is at a slight angle to the line joining the centre ofthe pivot of the bell-crank lever to the centre of the pivot pin of saidpawl in the normal position of the parts in such manner as to applyincreased torque to said ratchet wheel over the final angular movementof the bell-crank lever.

3. A hand tool for giving a turning movement to a work element such as anut, screw or stud, comprising a hollow head, an opening in said head, aratchet wheel mounted within said head and accessible via said opening,at least one spring-controlled pawl carried within and by said head andin engagement with said ratchet wheel, a hollow handle connected to saidhead, said pawl being adapted on rotation of said head by means of saidhandle to effect rotation of said ratchet wheel in one direction only, astirrup piece rotatably mounted about the axis of said ratchet wheel, apivot rod carried by said stirrup piece, a spring-controlled pawlcarried by said pivot rod and adapted on bodily rotation about theformed with a guide slot with which said pivot rod is in slidingengagement, a rod passing right through said hollow handle and pivotallyconnected at its upper end to the other arm of said bell-crank lever,and a trigger mechanism pivotally mounted on said hollow handle andpivotally connected to the lower end of said rod.

4. A hand tool according to claim 3, wherein said handle is formed witha recess to accommodate the trigger mechanism when depressed, therebyincreasing its angle of movement.

5. A hand tool according to claim 3, comprising spring means forreturning the trigger mechanism to its normal position after actuation.

6. A hand tool according to claim 3, wherein adjusting means areprovided at the pivotal connection between said rod and the bell-cranklever.

7. A hand tool for giving a turning movement to a a work element such asa nut, screw or stud, comprising a hollow head, an opening in said head,a ratchet wheel mounted within said head and accessible via saidopening, at least one spring-controlled pawl carried within and by saidhead and adapted to effect rotation of said ratchet wheel in onedirection only by bodily rotation of said head about the axis of saidratchet wheel, a stirrup piece rotatably mounted about the axis of saidratchet wheel, a pivot rod mounted in elongated pivot holes in saidstirrup piece, a spring-controlled pawl carried by said pivot rod andadapted on bodily rotation about the axis of said ratchet wheel toeffect rotation of said ratchet wheel in the same direction as before, abell-crank lever fulcrumed in said head, one arm of said lever beingformed with a guide slot with which said pivot rod is in slidingengagement, said elongated pivot holes being at right angles to saidguide slot in the normal position of said bell-crank lever, and meansfor rotating said bell-crank lever about said fulcrum.

8. A ratchet spanner, comprising a hollow head having an openingtherein, a ratchet wheel mounted within said head and accessible viasaid opening, at least one spring-controlled pawl carried within and bysaid head and adapted to effect rotation of said ratchet wheel in onedirection only by bodily rotation of said head about the axis of saidratchet wheel, a stirrup piece rotatably mounted about the axis of saidratchet wheel, a pivot rod carried by said stirrup piece, aspring-controlled pawl carried by said pivot rod and adapted on bodilyrotation about the axis of said ratchet wheel to effect rotation of saidratchet wheel in the same direction as before, a bell-crank leverfulcrumed in said head, one arm of said lever being formed with a guideslot with which said pivot rod is in sliding engagement, and means forrotating said bell-crank lever about said fulcrum.

References Cited in the file of this patent UNITED STATES PATENTS616,540 King Dec. 27, 1898 714,586 Landis Nov. 25, 1902 1,398,180Dietrich Nov. 22, 1921 1,970,721 Walton Aug. 21, 1934 2,633,044Pasquariello Mar. 31, 1953

